This invention relates to roll paper wrapping apparatus and more particularly roll header heat plates which may be assembled from multiple interchangeable sections and to protective wrapping for newsprint and fine paper rolls having a series of grooves in side edges that eliminate the formation of indentations in the ends of the paper rolls due to ridges in overlapping end wrap paper.
Newsprint and other forms of paper are manufactured and processed as large elongated sheets or webs. For storage and transport, the paper stock is wrapped around a core plug to form a cylindrical roll. The rolls are very heavy. A typical roll may range from 25 to 72 inches in diameter. To protect the roll from moisture, the atmosphere, and physical abrasions, the roll itself is wrapped in a moisture proof protective wrapping. Typically the rolls are then stacked one on the other and stored on end. Specialized machinery must be employed to automatically apply wrapping paper to the large rolls.
Various methods previously have been used to wrap paper rolls. One of the most successful methods has been to first wrap the roll in one or two layers of a protective wrapping paper, with the wrapping paper extending outwardly beyond the ends of the roll. Next, interior roll headers (disks formed of corrugated cardboard, chipboard, or laminated kraft paper) are fitted inside the wrapping paper against the ends of the roll. The wrapping paper is then crimped over the edges of the interior headers at the ends of the rolls using a crimping wheel. A set of exterior or outside roll headers (somewhat thinner disks typically formed of a kraft paper with a poly coating on the inside surface) are then attached to the ends of the roll over the crimped edges. The headers and the wrapping paper are held in place and affixed to one another through the use of a heat sensitive adhesive (the poly coating) on the inside surface of the outside roll header.
To affix the outside roll headers to the ends of the rolls in a typical roll wrapping machine, a roll is placed longitudinally between a pair of header heat plates. Each header heat plate is provided with a plurality of vacuum holes, which are used to temporarily secure a roll header to the header plate. A plurality of heating elements attached to the header heat plate heat the plate itself. The heat plate activates the heat sensitive adhesive on the inside surface of the outside roll header and simultaneously presses the outside roll header against the crimped wrapping paper and inside roll header on the end of the roll. The header heat plate is then disengaged from the roll header, leaving the two headers and wrapping paper firmly attached to the end of roll.
A typical heat plate is an assembly of several components. A one piece aluminum face plate one and one-half inch thick contacts the roll headers. Separate elongated heating elements (there may be thirty-six or so strip heaters) are mounted on the rear side of the face plate in order to heat to the face plate. The strip heaters are spaced apart and arranged to provide a uniform distribution of heat while not interfering with the vacuum holes in the face plate. Each heater element is individually bolted to the face plate and electrically routed to a power source. Spacer plates in the form of cross bars fit between the strip heaters, and an element back plate is mounted over the spacer plates. A layer of insulation board is mounted over the element back plate, and a header back plate is mounted over the insulation. The whole assembly is held together by bolts that extend through the plates.
The aforementioned system has several disadvantages. Each header plate is very large, heavy, complicated, and expensive. Due to the heat and pressure and physical conditions involved with affixing roll headers to a roll, the header plate is readily susceptible to damage. Replacement of an entire header plate is cumbersome, time-consuming, and expensive. Additionally, the replacement header plate must be manually fitted with the heating elements before it can be used. This is labor intensive and expensive.
It is an object of the present invention to provide a header heat plate which may be easily assembled and is less cumbersome and expensive to replace. It is also an object of the invention to provide a header heat plate wherein a damaged portion of the header heat plate can be replaced without necessitating replacement of the entire unit and without requiring that a complete replacement header heat plate be maintained in inventory. It is another object of the invention to provide a header heat plate in which the heating elements are cast within the plate rather than manually fitted to the rear of the plate. It is still another object of the invention to accomplish the above objectives while still interfacing with conventional equipment in the industry.
The wrapping paper also forms an integral part in the protection of the roll. This wrapping paper is rolled around the roll after the interior roll headers have been affixed. The side edges of the wrapping paper usually extend six inches beyond the side edges of the roll. After the wrapping paper has been applied to the roll, the protruding edge is then crimped over the end. As the edges are crimped over, part of the wrapping paper overlaps onto itself forming raised areas or ridges in the wrapper (FIG. 7). Due to the extreme weight involved in storing these heavy paper rolls in stacks on their ends, the ridges are permanently indented into the soft paper ends of the rolls. These indentations are very disadvantageous and cause the paper to tear when unrolled. Additionally, as a result of the ridges, a distorted edge can be produced in the final paper product.
It is another objective of the present invention to provide a wrapping paper that will not produce ridges in the crimped ends of the wrapping paper when the rolls are stacked on their ends.